During 2005, US doctors performed a record 180 million X-ray assisted procedures and, worldwide the number surpassed 2.5 billion. Over 500 million square meters of human tissue is exposed annually to artificially generated X-rays.
Although the health benefits are undeniable, the growing use of X-rays is also responsible for a dramatic increase in a number of related ailments. X-rays can damage cell structures with immediate or delayed consequences. Most serious of all are the 30,000 new cases of radiation induced cancers diagnosed every year, 5700 in the US alone. Of particular concern is fluoroscopy where the incidence of fatal cancers may be as high as 1 per 1000 exposures.
The amount of radiation to which a patient is exposed depends on a number of factors, including the sensitivity of the radiation detector used and the amount of visual information necessary to successfully perform the procedure.
The sensitivity of the radiation detector is determined by the current state of technology. The industry is moving toward a film-free infrastructure where X-ray films are replaced by amorphous silicon detector arrays and images are enhanced and archived digitally. Although digital systems are more convenient, the resolution of the digital systems lags behind that of X-ray film.
To accommodate the requirements of various medical procedures, the information obtained from the areas of interest requires the maximum resolution possible while, at the same time, exposing the patient to a minimum amount of radiation. Because all known X-ray sources generate an essentially uniform output beam, health care providers may use specially shaped shields to cover parts of the patient's body (and their own), while exposing the areas of interest to the X-ray beam. These shields are generally made of lead and are manufactured prior to the procedure.